Display device, liquid crystal display device, and method for manufacturing display device

ABSTRACT

A display device displays images with a plurality of signal lines and includes spare lines, each being arranged to be connectable to the signal lines so as to be used for recovery of the signal lines from disconnection. Each of the spare lines has constricted sections for cutting. With this arrangement, it is possible to easily and properly recover the signal lines from disconnection.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to spare lines for recovery fromdisconnection and a common line for the prevention of excess current,both of which are provided in a display device.

2. Description of the Related Art

Active-matrix liquid crystal display devices, for instance, have aplurality of data signal lines and scanning signal lines arranged in amatrix pattern, together with thin-film transistors and pixel electrodesconnected to the transistors in the vicinity of intersection points ofthe data signal lines and the scanning signal lines. Display screenimages are displayed by changing the status of orientation of liquidcrystal upon feeding signal potential to the pixel electrodes throughthe data signal lines under on/off control of the thin-film transistorsthrough the scanning signal lines.

Recently, in response to a need for better quality of display images,the width of the data signal lines has become extremely narrow, namely,less than 10 μm, and in actual instance, 6 μm. As a result, breaks tendto occur in a manufacturing process. For instance, dust getting induring film formation and only a pinhole appearing on a resist maskduring etching result in breaks. Such breaks in the data signal linescause black lines in normally black mode or bright lines in normallywhite mode on a screen because proper signal potential cannot be fed tothe pixel electrodes located behind the breaks. Thus, a critical defectin the quality of display images arises.

As a solution for recovery from such disconnection, the following methodhas been suggested. That is to say, spare lines are provided so as toextend from the vicinity of the signal input-side ends of data signallines toward the vicinity of the opposite ends (i.e., below a displayarea), passing through an external substrate of a panel. The end of aline part behind a break in the data signal line is connected to thespare line by laser melting, so that signals can be supplied to the linepart behind the break. According to the method above, the spare linesare formed in advance in a pattern as illustrated in FIG. 7 below thedisplay area (i.e. in a lower area of the panel), so that the brokendata signal line is connected to one of the spare lines for recoveryfrom defects.

With regard especially to large-size display devices such as televisionsand monitors, a spare line is wide, and a line part behind a connectionpoint (an unnecessary line part) is long. This increases a load on theunnecessary line part. Therefore, as illustrated in FIG. 8, theunnecessary line parts (shaded portions in the figure) have to beremoved.

However, a wide spare line is not easy to cut by laser cutting, forinstance. This gives rise to the problem that cutting is laborious orproper cutting is impossible.

SUMMARY OF INVENTION

In order to solve the problems above, preferred embodiments of thepresent invention provide a display device which enables a signal linerecover from disconnection easily and properly.

In order to solve the problems above, a display device according to apreferred embodiment of the present invention which displays images witha plurality of signal lines, includes: spare lines each being arrangedto be connectable to the signal lines directly or via a line or the likeso as to be used for recovery of the signal lines from disconnection,wherein each of the spare lines has constricted sections for cutting.The signal lines may be any lines as long as they are communicationpaths of a display device, such as data signal lines.

According to the arrangement described above, when a signal line has abreak, for instance, a signal input-side end and the other end (endpoint) of the signal line, which other end is behind the break inrelation to the signal input side, can be connected (by melting, forinstance) to the spare line. This enables signals to be supplied to aline part behind the break in the signal line via the spare line. In thearrangement above, the spare line has the constricted sections forcutting. That is to say, by cutting the spare line at its constrictedsection, it is possible to easily remove a portion (a portion of thesignal line and a portion behind a connection point of the signal lineand a relay line) which is irrelevant to signal transfer through thespare line. Thus, it is possible to recover an unusable line portionbehind the break in relation to the side of signal input, accordinglysolve display defects due to the break, and save a lot of trouble duringthe recovery. The constricted sections are preferably formed in thevicinity of the end opposite to the signal input-side end of the signallines.

The display device according to a preferred embodiment of the presentinvention may further include relay lines each intersecting apredetermined number of the signal lines and intersecting any of thespare lines. According to the arrangement above, the relay lines areprovided between the spare lines and the signal lines. This makes itpossible to reduce intersection points of the spare lines and the signallines, thus reduce adverse effect such as parasitic capacitance.

According to the arrangement above, in case there is a broken signalline, a predetermined relay line is connected to the signal line and aspare line. The spare line is cut at its constricted section which islocated behind a connection point of the spare line and the relay line.By providing the constricted section in the vicinity of (or preferablyright behind) the connection point, more unnecessary line portions(portions irrelevant to signal transfer through the spare line) can beremoved. Thus, an unusable line portion behind a break in relation tothe side of signal input is recovered.

The display device according to a preferred embodiment of the presentinvention may be arranged such that the constricted sections are locatedbetween groups of one relay line or a predetermined number of relaylines.

This makes it possible to make the intersecting (directly connectable)point of the spare line and the relay line close to the constrictedsection. Thus, it is possible to accurately recover a line portionbehind a break (an unusable line portion) from disconnection by cuttingmore unnecessary line portion (a portion irrelevant to signal transferthrough the spare line) off.

In order to solve the problems above, the display device according to apreferred embodiment of the present invention which displays images witha plurality of signal lines, includes a common line to which an excesscurrent flowing in the signal lines is let out, the common line havingconstricted sections for cutting.

According to the structure above, in case of a short-circuit in a signalline and a common line for some reason, it is possible to easily cut thecommon line at its constricted section. Thus, it is possible to reducethe load of the common line on the short-circuited signal line and alsosave trouble during the cutting.

The display device according to a preferred embodiment of the presentinvention is a display device having a display section in which aplurality of data signal lines is provided, includes a plurality ofspare lines, provided around the display section, being used forrecovery of the data signal line from disconnection, wherein a pluralityof constricted sections is formed at an interval on each of the sparelines along an edge opposite to a data input side edge of the displaysection.

According to the arrangement above, when disconnection occurs in a datasignal line, an end of the data signal line is connected to a spare linedirectly or via a line, and the spare line is cut at its constrictedsection behind the connection point in relation to the side of signalinput. Thus, it is possible to recover the data signal line fromdisconnection, to reduce a load resulting from a portion that isirrelevant to signal transfer, and to save trouble during the recovery.

The display device is preferably such that a relay line is arranged soas to extend between two adjacent constricted sections toward an end ofthe data signal line.

The display device may be arranged such that: at least one of the sparelines is connected to the relay line by melting; the spare line is cutat its constricted section that is immediately behind a connection pointby melting in relation to a signal input side; and the relay line isconnected to a broken data signal line by melting.

A liquid crystal display device according to another preferredembodiment of the present invention includes the above display device.

In order to solve the problems above, a method for manufacturing adisplay device according to yet another preferred embodiment of thepresent invention includes the steps of: forming a spare line that isarranged to be connectable to the signal line directly or via a relayline so as to be used for recovery of the signal line fromdisconnection, and forming a constricted section on the spare line at aposition behind a connectable point with the signal line or the relayline; checking whether there is a broken signal line or not; and in acase where there is a broken signal line, connecting the broken signalline to the spare line, and cutting the spare line at the constrictedsection.

As described above, according to the display device, when a signal linehas a break, for instance, a signal input-side end and the other end(end point) of the signal line, which other end is behind the break inrelation to the signal input side, are connected to the spare line. Thisenables signals (signal potential) to be supplied to a line portionbehind the break in the signal line via the spare line. In thearrangement above, the spare line has the constricted sections forcutting. That is to say, by cutting the spare line at its constrictedsection, it is possible to significantly easily remove a portion whichis irrelevant (an unnecessary line part) to signal transfer through thespare line. Thus, it is possible to easily and properly recover thesignal lines from disconnection.

Other features, elements, processes, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of the arrangement of the substantial portion(after recovery from defects) of a display device according to apreferred embodiment of the present invention.

FIG. 2 is a plan view of the arrangement (before recovery from defects)of a display device according to a preferred embodiment of the presentinvention.

FIG. 3 is a plan view of the arrangement (after recovery from defects)of a display device according to a preferred embodiment of the presentinvention.

FIG. 4 is a plan view of the arrangement of the substantial portion(before recovery from defects) of a display device according to apreferred embodiment of the present invention.

FIG. 5 is a plan view of the arrangement of the substantial portion(under recovery from defects) of a display device according to apreferred embodiment of the present invention.

FIG. 6 is a plan view of the substantial portion of another displaydevice according to a preferred embodiment of the present invention.

FIG. 7 is a plan view of the arrangement of the substantial portion(before recovery from defects) of a conventional display device.

FIG. 8 is a plan view of the arrangement of the substantial portion(after recovery from defects) of the conventional display device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following will describe preferred embodiments of the presentinvention with reference to FIGS. 1 to 6.

FIG. 2 illustrates the display device of the present preferredembodiment before the recovery of lines from disconnection. FIG. 3illustrates the display device after the recovery of lines fromdisconnection. As illustrated in FIG. 2, the display device 1 includes aconnection section 3, a panel 7, spare lines SPL1 to SPL14, input-siderelay lines RL, and non-input-side relay lines rL. In the panel 7, adisplay area 10 is provided. In the display area 10, a plurality of datasignal lines is arranged vertically in the figure; a plurality ofscanning signal lines is arranged horizontally in the figure. In thevicinity of intersection points of the data signal lines and thescanning signal lines, thin-film transistors and pixel electrodes areprovided. However, these components are omitted in FIGS. 2 and 3. InFIG. 3, only data signal lines S1 to S7 with breaks are illustrated (InFIG. 3, a symbol×represents a break). Data signals are sent throughnormal data signal lines without breaks downwards (i.e., from a datasignal input side to a non-data-signal-input side) in the figure.Scanning signals are sent through the scanning signal lines from left toright or from right to left in the figure. The display area 10 isdivided into 14 display blocks A through N. Each of the display blockshas a predetermined number (300 to 400) of data signal lines.

The connection section 3 is provided above the display area 10 (abovethe upper edge of the display area 10) and composed of connection blocksa through n respectively corresponding to the display blocks A throughN. Each of the connection blocks is connected to data signal linesresiding in a corresponding display block, and includes two adjacentcircuits, each of which includes one terminal and one buffer connectedto the terminal on the input side.

Each of the spare lines SPL1 through SPL14 has an end which is connectedto the output of the buffer in the connection block. The spare linesSPL1 through SPL14 extend along the outer edges of the panel 7 (alongthe left outer edge of the panel 7 for SPL1 through SPL7 and along theright outer edge of the panel 7 for SPL 7 through 14) toward an areabelow the display area 10 in the panel 7 (i.e., an area outside thelower edge of the display area 10 and a lower area of the panel). In thearea below the display area 10, the spare lines SPL1 through 14 extendin the direction along the scanning lines. For instance, a spare lineSPL2 has an end which is connected to the outputs of buffers in aconnection block b. The spare line SPL2 extends along the left outeredge of the panel 7 toward the area below the display area 10 in thepanel 7. In the area below the display area 10, the spare line SPL2extends in the direction along the scanning lines. Similarly, a spareline SPL13 has an end which is connected to the outputs of buffers in aconnection block m. The spare line SPL13 extends along the right outeredge of the panel 7 toward the area below the display area 10 in thepanel 7. In the area below the display area 10, the spare line SPL13extends in the direction along the scanning lines. Before recovery fromdisconnection (FIG. 2), two spare lines (pair of SPL1 and SPL14, pair ofSPL2 and SPL13 . . . ) coming from the both sides of the panel 7 areconnected to each other inside the area below the display area 10.

What is notable here is that each of the spare lines (SPL1 throughSPL14) has constricted sections (narrow sections) to be cut forrepairing disconnections in the area below the display area 10 (i.e.,the vicinity of the opposite side of signal input of the data signallines).

Input-side relay lines RL are provided between the display area 10 andthe connection section 3. That is to say, two input-side relay lines RLextending in the direction along scanning lines are arranged in parallelbetween adjacent two display blocks and two connection blockscorresponding to the display blocks. One input-side relay line isconnected to terminals in one connection block; the other input-siderelay line is connected to terminals in the other connection block. Withthis arrangement, it is possible to recover two data signal lines of thedata signal lines residing in two display blocks from the disconnection.That is to say, it is possible to recover a maximum of 14 data signallines in total from disconnection. Note that it is possible to recovertwo data signal lines in one display block from disconnection. Forinstance, two input-side relay lines RL1 and RL2 extending in thedirection along scanning lines are provided in parallel between adjacenttwo display blocks E and F and two connection blocks e and f. Theinput-side relay line RL1 is connected to terminals in the connectionblock e; the input-side relay line RL2 is connected to terminals in theconnection block f.

As illustrated in FIG. 2, non-input-side relay lines are provided belowthe display blocks A through N (i.e., below the lower edges of thedisplay blocks). Each of the non-input-side relay lines preferably hasthe shape of a reverse ‘L.’ More specifically, one line portion of thenon-input-side relay line extends in the direction along the data signallines, and the other line portion faces the display blocks. The lineportion extending along the data signal lines is shorter than the otherline portion facing the display blocks although the non-input-side relaylines are deformed in FIGS. 2, 1, 4, and other drawings. In FIG. 2, twolarge non-input-side relay lines and two small non-input-side relaylines are arranged in the direction in which scanning lines extend, suchthat the large one and the small one are arranged alternately. However,the present preferred embodiment is not limited to this arrangement.Alternatively, four large non-input-side relay lines and four smallnon-input-side relay lines may be arranged in the direction in which thescanning lines extend, such that the large one and the small one arearranged alternately.

FIG. 4 is an enlarged view of an area X illustrated in FIG. 2. Asillustrated in the figure, non-input-side relay lines rL1 through rL4each of which preferably has the shape of a reverse ‘L’ are arrangedbelow a display block E. The non-input-side relay lines rL1 through rL4are arranged in order of the large non-input-side relay line rL1, thesmall non-input-side relay line rL2, the large non-input-side relay linerL3, and the small non-input-side relay line rL4 in the direction inwhich the scanning lines extend. As illustrated in FIG. 4, each of thedata signal lines in the display block E intersects with a (longer) lineportion of any of the non-input-side relay lines rL1 through rL4. Theother (shorter) line portion of the non-input-side relay line (rL1, rL2,rL3, and rL4) intersects with the seven spare lines SPL1 through SPL7(partially illustrated in FIG. 4) extending in the direction along thescanning lines, as illustrated in FIGS. 2 and 4. The constrictedsections w of the spare lines SPL1 through SPL7 is formed between anon-input-side relay line rL4 corresponding to the block D and thenon-input-side relay line rL1 corresponding to the block E, between thenon-input-side relay line rL2 corresponding to the block E and thenon-input-side relay line rL3 corresponding to the block E, and betweenthe non-input-side relay line rL4 corresponding to the block E and anon-input-side relay line rL1 corresponding to the block F.

More specifically, in FIG. 2, the data signal lines in any of displayblocks A through N intersect with any of four non-input-side relay linescorresponding to the display block. Each of the spare lines SPL1 throughSPL7 intersects with four non-input-side relay lines corresponding toeach of the display blocks A through G. Each of the spare lines SPL8through SPL14 intersects with four non-input-side relay linescorresponding to each of the display blocks H through N. At a regularinterval, the constricted sections of the spare lines SPL1 through SPL7are formed between a second non-input-side relay line from the leftcorresponding to a display block and a third non-input-side relay linefrom the left corresponding to the display block, and between a fourthnon-input-side relay line from the left corresponding to the displayblock and a first non-input-side relay line from the left correspondingto its adjacent display block (on the right). This arrangement makes theconnection point of a spare line and a non-input-side relay line closeto a constricted section. Thus, more unnecessary line portions (portionsof a spare line irrelevant to signal transfer) can be removed.

Recovery of signal lines in a wiring pattern illustrated in FIG. 2 fromdisconnection is made as illustrated in FIGS. 3, 5, and 1. The followingdescribes how to recover broken data signal lines S3 and S4, which isthe same for other data signal lines. The line portion of thenon-input-side relay line rL along the data signal lines is shorter thanthe other line portion although the line portions of the non-input-siderelay line are deformed in FIGS. 1, 3, and 5.

First, a broken data signal line (data signal input-side end) and aspare line are connected through an input-side relay line RL in an areaabove the display area (in an area above the upper edge of the displayarea 10). As for the broken data signal line S3, for instance, thesignal line S3 and an input-side relay line RL1 are connected by lasermelting. Similarly, as for the broken data signal line S4, the signalline S4 and an input-side relay line RL2 are connected by laser melting.

Second, a data signal non-input-side end (endpoint) of the broken datasignal line and the spare line are connected through a non-input-siderelay line rL in an area below the display area 10 (in an area below thelower edge of the display area 10). As for the broken data signal lineS3, for instance, an end point of the data signal line S3 and the longerline portion of a non-input-side relay line rL2 are connected to eachother by laser melting. The shorter line portion of the non-input-siderelay line rL2 and a spare line SPL6 are also connected by lasermelting. As for the broken data signal line S4, an end point of the datasignal line S4 and the longer line portion of a non-input-side relayline rL3 are connected by laser melting. The shorter line portion of thenon-input-side relay line rL3 and a spare line SPL5 are also connectedby laser melting.

Third, the spare line connected to the broken signal line is cut at itsconstricted section via a laser. For instance, the spare line SP6connected to the broken data signal line S3 (through the non-input-siderelay line rL2) is cut at its constricted section w which is locatedbetween the non-input-side relay line rL2 and the non-input-side relayline rL3. The spare line SPL5 connected to the broken data signal lineS4 (through the non-input-side relay line rL3) is cut at its constrictedsection w which is located between a non-input-side relay line rL4 and anon-input-side relay line rL1 corresponding to a display block F.

The above-described processes enable a signal potential to be fed to aline portion behind the break in the data signal line S3 via theinput-side relay line RL1 that is one of the input-side relay linescorresponding to the display blocks E and F, terminals and buffers ofthe connection block F, the spare line SPL6, and the non-input-siderelay line rL2. Thus, display defects due to disconnection are solved. Asignal potential is fed to a line portion behind the break in the datasignal line S4 via the input-side relay line RL2 that is one of theinput-side relay lines corresponding to the display blocks E and F,terminals and buffers in the connection block e, the spare line SPL5,and the non-input-side relay line rL3. Thus, display defects due todisconnection are solved.

Thus, according to various preferred embodiments of the presentinvention, it is possible to easily remove a portion of the spare lineSPL which is irrelevant to signal transfer (a portion behind theconnection point of a spare line and a relay line rL) by cutting thespare line SPL at its constricted section w. As a result, it is possibleto accurately recover portions behind breaks in the data signal lines S1through S7 from disconnection and save a lot of trouble during therecovery.

The present preferred embodiment has been described with reference to anarrangement in which the constricted sections are formed on the sparelines which are provided for recovery of signal lines fromdisconnection. However, the present preferred embodiment is not limitedto this arrangement. Alternatively, the present preferred embodiment mayinclude, for example, the arrangement as illustrated in FIG. 6, i.e.,the arrangement in which constricted sections w for cutting are providedin a common line to which an excess current fed from the data signallines through switching elements such as MOS transistors (Tr) is letout.

In the event of a short circuit (leakage) in a data signal line and acommon line due to a foreign object and others, the quality of displayimages degrades because the load for the common line is applied to thedata signal lines. In order to avoid this problem, the common line iscut. However, cutting a wide common line of a large display device orthe like takes a lot of trouble.

In view of this, it is possible to accurately repair display defects dueto the short circuit without a lot of trouble by cutting the common lineat its constricted section w illustrated in FIG. 6.

The present invention is not limited to the description of the preferredembodiments above, but may be altered by a skilled person within thescope of the claims. A preferred embodiment based on a propercombination of technical means disclosed in different preferredembodiments described herein is encompassed in the technical scope ofthe present invention.

The display device according to various preferred embodiments of thepresent invention is suitably applicable to, for instance, large liquidcrystal display televisions and a monitor.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1. A display device which displays images with a plurality of signallines, comprising: a display area; a plurality of signal lines; and atleast one line arranged to at least partially overlap the plurality ofsignal lines but not electrically connected to the plurality of signallines outside of the display area, the at least one line including aplurality of narrower sections that are narrower than another portion ofthe at least one line, each of the plurality of narrower sections beingarranged between two of the plurality of signal lines; wherein at leastone of the plurality of narrower sections is arranged between two of theplurality of signal lines that are adjacent to each other among theplurality of signal lines.
 2. The display device of claim 1, wherein theat least one line includes a plurality of lines arranged to at leastpartially overlap the plurality of signal lines but not electricallyconnected to the plurality of signal lines.
 3. The display device ofclaim 1, wherein each of the plurality of narrower sections is arrangedbetween two of the plurality of signal lines that are adjacent to eachother among the plurality of signal lines.
 4. The display device ofclaim 1, wherein the at least one line is at least one spare line. 5.The display device of claim 1, wherein the at least one line includes aplurality of spare lines.
 6. The display device of claim 1, wherein theat least one line is arranged to be connected to at least one of theplurality of signal lines to enable recovery from a disconnection in theat least one of the plurality of signal lines.
 7. The display device ofclaim 1, wherein each of the plurality of narrower sections is arrangedto be cut so as to enable recovery from a short circuit between at leastone of the plurality of signal lines and the at least one line.
 8. Thedisplay device of claim 1, wherein each of the plurality of narrowersections includes a constricted section of the at least one line.
 9. Thedisplay device of claim 1, wherein a sum of lengths of the plurality ofnarrower sections defines a minor portion of a length of the at leastone line.